Polyunsaturated fatty acids (PUFA) such as the omega-3 fatty acids are vital to everyday life and function. For example, the beneficial effects of omega-3 fatty acids like cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) on lowering serum triglycerides are now well established. These compounds are also known for other cardioprotective benefits. See e.g., Dyrberg, at al., In: ω-3 Fatty Acids: Prevention and Treatment of Vascular Disease. Kristensen, et al., eds., Bi & Gi Publ., Verona-Springer-Verlag, London, pp. 217-26, 1995; O'Keefe and Harris, Am. J. Cardiology 2000, 85:1239-41; Radack et al., “The effects of low doses of omega-3 fatty acid supplementation on blood pressure in hypertensive subjects: a randomized controlled trial.” Arch. Intern. Med 1991, 151:1173-1180. Indeed, the American Heart Association has also reported that omega-3 fatty acids can reduce cardiovascular and heart disease risk. Other benefits of PUFAs are those related to the prevention and/or treatment of inflammation, neurogenerative diseases, and cognitive development. See e.g., Sugano, Michihiro, “Balanced intake of polyunsaturated fatty acids for health benefits.” J. Oleo Sci. 2001, 50(5):305-311. Diets rich in PUFA's like omega-3 fatty acids have also been shown to have beneficial effects for heart disease, cancer, arthritis, allergies, and other chronic diseases. (See e.g., The American Heart Association, Scientific Statement, “Fish Consumption, Fish Oil, Omega-3 Fatty Acids and Cardiovascular Disease,” November 2002; Appel et al., “Does supplementation of diet with ‘fish oil’ reduce blood pressure? A meta-analysis of controlled clinical trials.” Arch. Intern. Med 1993, 153(12):1429-1438; GISSI-Prevenzione Investigators. “Dietary supplementation with omega-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial.” Lancet 1999, 354:447-455.)
Polyunsaturated fatty acids, such as, for example omega-3 fatty acids, are often derived from marine oils, microbial, and/or algal oils. Such sources typically provide the PUFA in a triglyceride form where other undesired, fatty acids (e.g., saturated fatty acids) are present along side a desired PUFA in the triglyceride molecule. Thus, purifying and concentrating PUFA's in a triglyceride form is generally desired.
Several methods of producing PUFA concentrates from oils, such as marine, microbial, and/or algal oils, are known, for example, selective lipase hydrolysis, PUFA complexation using urea (or more sophisticated molecular guest-host frameworks involving metric control), and a physical removal of unwanted components by fractionation. U.S. Pat. No. 6,846,942 describes the separation of EPA from DHA by precipitating EPA magnesium salt. Fractionation involving molecular distillation is usually conducted on ethyl esters prepared from the starting triglycerides since they are more volatile than corresponding triglycerides. So this method requires the additional step of converting the triglycerides to ethyl esters. Since ethyl esters of PUFA are usually not as bioavailable as their triglyceride counterparts, the PUFA ethyl esters are typically re-esterified to the corresponding triglycerides.
A need exists to remove at least a fraction of the saturated free fatty acids and other undesirable components from a glyceride, such as for example, a triglyceride, and to concentrate the PUFA fraction on the glyceride. The compositions and methods disclosed herein meet these and other needs.